Photosynthesis Photosynthesis Photosynthesis Click below to see video

Photosynthesis

Photosynthesis

Photosynthesis Click below to see video • http: //www. youtube. com/watch? v=z. Eg. IO 9 Kq 2_Y

What organelle would you expect to find in a plant cell that you won’t find in an animal cell? • Chloroplasts!

What happens in the chloroplast? • Photosynthesis!

What is photosynthesis? • Process of using energy from the sun to convert water and carbon dioxide to carbohydrates and oxygen

Photosynthesis in Overview • Process by which plants and other autotrophs store the energy of sunlight into sugars.

Why is that important to us? • We need to eat and breathe! • Photosynthesis provides us with the oxygen we need to breathe, and the food we need to eat to obtain energy !

What is an autotroph? • Autotroph = organisms that make their own food (plants and some bacteria) – Called producers (because they produce food)

What is a heterotroph? • Heterotroph = organisms that gets it energy requirements by consuming other organisms (animals) – Called consumers

Heterotrophs • Heterotrophs that eat only plants are herbivores – Cows, rabbits, grasshoppers • Heterotrophs that prey on other heterotrophs are called carnivores – Wolves, lions, hawks

• Heterotrophs that eat both plants and animals are called omnivores – Bears, humans, mockingbirds • Heterotrophs that eat fragments of dead matter are called detritivores – Worms, aquatic insects that live on stream bottoms

• Heterotrophs that break down dead organisms by releasing digestive enzymes and absorbing nutrients are called decomposers • Without Detritivores and Decomposers, the entire biosphere would be littered with dead organisms!

Trophic levels Steps in a Food Chain

Trophic levels • Autotrophs make up first trophic level • Heterotrophs make up the remaining trophic levels

What is energy? • Energy is the ability to do work. • All living things need energy! • Without energy, life would not exist!

Energy • May be Kinetic or Potential energy 21

Kinetic Energy • Energy of Motion • Heat and light energy are examples 22

Potential Energy • Energy of position • Includes energy stored in chemical bonds 23

Cellular Energy

Cellular Energy • Adenosine = adenine + ribose • ATP - adenosine tri(3)phosphate used by the cell for energy – Energy currency – Energy stored in PO 43 - bonds • ADP - Adenosine Di(2)phosphate used to regenerate ATP

ATP • Components: 1. adenine: nitrogenous base 2. ribose: five carbon sugar 3. phosphate group: chain of 3 Phosphate group adenine P ribose P P

How does ATP work ? • Organisms use enzymes to break down energy-rich glucose to release its potential energy • This energy is trapped and stored in the form of adenosine triphosphate(ATP)

Coupled Reaction - ATP • Energy used for growth, reproduction, movement and active transport • Drives most of cell’s activities H 2 O

Hydrolysis of ATP + H 2 O (exergonic) ADP + P Adenosine triphosphate (ATP) P P P Hydrolysis (add water) P P + P Adenosine diphosphate (ADP)

Hyrolysis is Exergonic Energy Used by Cells Copyright Cmassengale

Dehydration of ATP ADP + P (endergonic) ATP + H 2 O Dehydration (Remove H 2 O) P P + P Adenosine diphosphate (ADP) Adenosine triphosphate (ATP) P P P Copyright Cmassengale

Dehydration is Endergonic Energy is restored in Chemical Bonds Copyright Cmassengale

Terminology Review • Autotroph – Obtains energy from light • Heterotroph – Obtains energy from other sources • Trophic levels – Ex. Sun – plant – herbivore – carnivore • Photosynthesis – Process by which light energy is converted to chemical energy • Cellular respiration – Process used to harvest energy from organic compounds

More to come! Quiz next time (8. 1)

Terminology Review • Autotroph – Obtains energy from light • Heterotroph – Obtains energy from other sources • Trophic levels – Ex. Sun – plant – herbivore – carnivore • Photosynthesis – Process by which light energy is converted to chemical energy • Cellular respiration – Process used to harvest energy from organic compounds

Photosynthesis Chapter 8. 2

Photosynthesis Overview • Sun – The source of energy for all living things! • Photosynthesis – Taking in light energy and changing it to chemical energy – Occurs in the chloroplasts of autotrophs

Photosynthesis in Overview • Process by which plants and other autotrophs store the energy of sunlight into sugars. • Requires sunlight, water, and carbon dioxide. • Overall equation: 6 CO 2 + 6 H 20 C 6 H 12 O 6 • Occurs in the leaves of plants in organelles called chloroplasts. + 6 O 2

Leaf Structure • Gas exchange of CO 2 and O 2 occurs at openings called stomata surrounded by guard cells on the lower leaf surface.

Chloroplasts • Found in leaves of plants • Site of photosynthesis • Composed of: – grana - stacks of thylakoids contain pigment (chlorophyll) • site of light reaction – stroma - the fluid around the grana • site of dark reaction 1/12/2022 Page: 40

Chloroplast Structure • Inner membrane called the thylakoid membrane.

Chloroplast Structure • Thickened regions called thylakoids.

Chloroplast Structure • A stack of thylakoids is called a granum. (Plural – grana)

Chloroplast Structure • Stroma is a liquid surrounding the thylakoids.

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Pigments • Photosynthetic organisms capture energy from sunlight with pigments • These pigments are embedded in the membranes of the chloroplast in groups called photosystems.

Pigments • Chlorophyll A is the most important photosynthetic pigment. • Other pigments are also present in the leaf. – Chlorophyll B – Carotenoids (orange / red) – Xanthophylls (yellow / brown)

Pigments • Chlorophylls absorb most strongly in the violet-blue region of the visible light spectrum and reflect light in the green region. That is why plants that have chlorophyll a appear green!

Light • White light - spectrum of many colors and wavelengths (ROYGBIV) • Carotenoids absorb mostly blue and green – Reflects red, yellow, and orange • Chlorophyll absorbs mostly blue and red light – Reflects green light 1/12/2022 Page: 50

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More to come! Quiz next time (8. 2)

Photosynthesis Ch 8. 3

Photosynthesis: The Chemical Process • Occurs in two main phases. – Light reactions – Dark reactions (aka – the Calvin Cycle) • Light reactions are the “photo” part of photosynthesis. Light is absorbed by pigments. • Dark reactions are the “synthesis” part of photosynthesis. Trapped energy from the sun is converted to the chemical energy of sugars.

Light Reactions • Light-dependent reactions occur on the thylakoid membranes. – Light and water are required for this process. – Energy storage molecules are formed. (ATP and NADPH) – Oxygen gas is made as a waste product.

Dark Reactions • Dark reactions (lightindependent) occur in the stroma. – Carbon dioxide is “fixed” into the sugar glucose. – uses ATP and NADPH molecules created during the light reactions to power the production of this glucose.

Light Reaction • Photosystem II (Grana, thylakoid membrane) – Light energy is absorbed by chlorophyll – Energy transferred to an electron – Excited electron exits to the Electron Transport Chain • Electron must be replaced – Water molecules split – Oxygen gas released – ETC forms ATP

Light Reaction • Photosystem I – The electrons are energized again (more light energy) – Energy is transferred to change NADP+ into NADPH • NADP+ is an electron carrier (takes the high energy electrons to the stroma for use in the light independent reaction Nicotinamide adenine dinucleotide phosphate

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From: http: //www. cat. cc. md. us/~gkaiser /biotutorials/photosyn/fg 4. html

Products • Products formed in the light reaction – 1. Oxygen gas (O 2) – released to atmosphere • From 2 water molecules being split – 2. ATP – to dark reaction (stroma) • From photosystem II – 3. NADPH - to dark reaction (stroma) • From photosystem I

Dark reaction • Occurs in stroma of chloroplast • Uses C & O from CO 2 and H from NADPH to form C 6 H 12 O 6 • Uses energy from ATP and NADPH • Calvin Cycle 1/12/2022 Page: 66

Carbon Fixation: • Carbon atoms from CO 2 are bonded or “fixed” into organic compounds • Carbon fixation: incorporation of CO 2 into organic compounds

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1/12/2022 PGAL From: http: //lhs. lps. org/staff/sputnam/ Page: Biology/U 4 Metabolism/calvincycle. png 69

Calvin cycle review • What goes in – 6 CO 2 – 18 ATP – 12 NADPH • What comes out – 1 glucose molecule » ADP, NADP+ 1/12/2022 Page: 70

Rate of Photosynthesis: • Affected by: – Light intensity – CO 2 Levels – Temperature – Availability of water 1/12/2022 Page: 71

Rate of Photosynthesis: • Light intensity: – as light intensity increases, the rate increases and then levels off 1/12/2022 Page: 72 From: http: //ghs. gresham. k 12. or. us/science/ps/sci/ib bio/cellenergy/photosynnotes/photosyn/intensity. htm

Rate of Photosynthesis: • CO 2 Levels: – increasing levels stimulates rate until plateau is reached 1/12/2022 Page: 73 From: http: //ghs. gresham. k 12. or. us/science/ps/sci/i bbio/cellenergy/photosynnotes/photosyn/dioxide. htm

Rate of Photosynthesis: • Temperature: – Raising temperature accelerates rate • Too hot - enzymes denature – Stomata will begin to close, limiting water loss and CO 2 entry 1/12/2022 From: http: //ghs. gresham. k 12. or. us/science/ps/sci/ ibbio/cellenergy/photosynnotes/photosyn/temp. htm Page: 74

Other Review • Problem set 1 • Problem set 2 1/12/2022 Page: 75

More to come! Quiz next time (8. 3)

How we use the products of Photosynthesis

How do we use the glucose and oxygen produced during photosynthesis? • We breath in the oxygen – it enters our lungs, diffuses into our bloodstream, and gets delivered to our cells. • We eat food, the food breaks down into molecules (remember learning about the macromolecules in Ch 2? ), diffuses into our bloodstream, and then gets delivered to our cells

• We can eat plants directly, (salads, fruits, cereal, vegetables) or we can eat meat from an animal that ate the plants (hamburger, steak, fish, chicken)

What happens once the oxygen and glucose gets delivered to our cells? • Cellular respiration!

Cellular respiration • C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + 36 ATP Remember the Photosynthesis equation?

Respiration is the process of extracting stored energy from glucose and storing it in the high energy bonds of ATP. The cells use ATPs to do cellular work!

Cellular Respiration • Happens in both Heterotrophs and autotrophs

Cellular Respiration • Takes place in 3 steps 1)Glycolysis 2)Krebs Cycle or Fermentation 3)Electron Transport Chain (comes after Krebs Cycle)

Glycolysis • Glycolysis occurs in all organisms! – In the cytoplasm of their cells • Glycolysis is the beginning of cellular respiration. • Does not require O 2.

Glycolysis • 1 glucose broken in half to form 2 pyruvic acid molecules (Pyruvate) • Releases small amount of energy. – Invest 2 ATP and get back 4 ATP - Net gain of 2 ATP – Gain 2 NADH (from NAD+)

Glycolysis • Occurs quickly- cells can produce thousands of ATP molecules in milliseconds! – But this isn’t enough, we need more from the respiration • Does not require oxygen! – Can supply chemical energy to cells when O 2 is not available.

Cellular Respiration • After the pyruvic acid molecules are formed during glycolysis, they will go to Cellular Respiration • There are two types of Respiration: Anaerobic Respiration and Aerobic Respiration

Vocab words! • Anaerobic respiration – No 02 • Aerobic respiration – With 02 1/12/2022 Page: 89

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Anaerobic Respiration • FERMENTATION • Occurs when in ABSENCE of O 2. • 2 Types • Lactic acid fermentation • Alcohol fermentation

Lactic Acid Fermentation • Pyruvic acid is converted into lactic acid – NADH to convert pyruvic acid to lactic acid – H+ taken from NADH makes NAD+ • used again for glycolysis

Examples • Bacteria used to create sauerkraut and buttermilk • Build up of lactic acid in muscle tissue. – You feel the lactic acid when you feel the ‘burn’ during exercise

Alcohol Fermentation • Pyruvic acid converted into ethyl alcohol in two steps – 1. CO 2 removed from pyruvic acid • Uses NADH – 2. H+ from NADH is transferred to make ethyl alcohol • Used again in glycolysis • Enzymes break down glucose into ethanol and CO 2.

Examples Bacteria and yeast – used to make: • Wine • Beer • Cheese • Bread

Next time we will learn about Aerobic Respiration

Aerobic Respiration

Remember 1/12/2022

Remember • If oxygen is not available, after glycolysis, the pyruvate goes into anaerobic respiration, either lactic acid or alcohol fermentation. – Learned about this last class

Remember • If oxygen is available, then the pyruvate will go into the Mitochondria and aerobic respiration – Two parts, Kreb cycle and the electron transport chain. – We will learn about this today

The Mitochondria • If O 2 is present, pyruvate is modified and enters the mitochondria. • Here food is broken down completely into CO 2. • Energy storage molecules like ATP are produced. This is why the mitochondria is called the power house of the cell.

Aerobic Respiration • After glycolysis – 90% of the energy that was in glucose is left within the bonds of the pyruvate • So in the presence of O 2 pyruvate passes to the second stage of arerobic cellular respiration within the matrix of the mitochondria, the Krebs cycle

Krebs cycle • Krebs cycle - named after Sir Hans Krebs • Also called the citric acid cycle • Pyruvic Acid enters and ATP, NADH, and CO 2 exits 1/12/2022 Page: 105

Krebs cycle • Once Pyruvate enters the mitochondria, one carbon atom becomes part of a molecule of CO 2 – Which will eventually be released into the atmosphere • The other two carbon atoms become part of a molecule called acetyl-Co. A

• The Acetyl Co. A will go through 2 turns of Krebs cycle

Krebs Cycle (Citric Acid Cycle) 1 Acetyl Co. A (2 C) OAA (4 C) Citrate (6 C) Krebs Cycle FADH 2 (one turn) FAD 2 CO 2 3 NAD+ 3 NADH ATP ADP + P

Krebs Cycle (Citric Acid Cycle) 1 Acetyl Co. A (2 C) OAA (4 C) Citrate (6 C) Krebs Cycle FADH 2 (two turns) FAD 2 CO 2 3 NAD+ 3 NADH ATP ADP + P

Krebs Cycle (Citric Acid Cycle) • Total net yield (2 turns of krebs cycle) 1. 2 - ATP 2. 6 - NADH 3. 2 - FADH 2 4. 4 - CO 2

Review of what we know so far • Glycolysis: – One glucose 2 pyruvic acids and 2 NADH and 2 ATP • Before Krebs: – 2 Pyruvic acids 2 acetyl Co. A, 2 NADH and 2 CO 2 • Krebs Cycle: – Two turns produce: • 6 NADH, 2 FADH 2, 2 ATP, 4 CO 2

Now to the Electron Transport Chain!

Electron Transport Chain • NADH and FADH 2 from Krebs move to the inner mitochondrial membrane and their high energy electrons convert ADP to ATP as they travel through the electron transport chain inner mitochondrial membrane

Electron Transport Chain Site of ETC Outer membrane Inner membrane space Matrix Cristae Inner membrane 115

Electron Transport Chain for NADH higher H+ concentration ATP + H Synthase Intermembrane Space 1 H+ E NADH + H+ NAD+ 2 H+ 3 H+ T C 2 H+ + 1/2 O 2 Inner Mitochondrial Membrane H 2 O ADP +P H+ ATP (Proton Pumping) Matrix 116

Electron Transport Chain for FADH 2 higher H+ concentration Intermembrane Space + 1 H E T FADH 2 + H+ FAD+ C 2 H+ + 1/2 O 2 (Proton Pumping) Matrix ATP + H + 2 H Synthase Inner Mitochondrial Membrane H 2 O ADP + P ATP + H 117

Oxygen: • O 2 is the final electron acceptor • Will also accept hydrogen ions (protons – H+) from ETC (NADH and FADH 2) – Forms H 2 O 1/12/2022 Page: 118

TOTAL ATP YIELD 1. 4 ATP – Glycolysis and Krebs Cycle – Glycolysis: 2 ATP – Krebs Cycle: 2 ATP 2. 32 -34 ATP – Electron Transport Chain 36 -38 ATP - TOTAL YIELD • Actual number varies from cell to cell • Aerobic respiration is 20 x more efficient than glycolysis alone ATP

Cellular Respiration Equation • C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + 36 ATP

Overview of photosynthesis and respiration SUN RADIANT ENERGY PHOTOSYNTHESIS GLUCOSE RESPIRATION CELL ACTIVITIES ATP(ENERGY)

EQUATION FOR PHOTOSYNTHESIS WATER 6 CO 2 + 6 H 2 O + ENERGY CARBON DIOXIDE OXYGEN C 6 H 12 O 6 + 6 O 2 GLUCOSE

EQUATION FOR RESPIRATION CARBON DIOXIDE GLUCOSE C 6 H 12 O 6 + 6 O 2 OXYGEN ATP 6 CO 2 + 6 H 2 O + ENERGY WATER

Energy and Exercise • Small amounts of ATPs are stored – enough for a few seconds of intense activity • Then muscle cells will use ATPs made by Lactic Acid Fermentation. This lasts about 90 seconds (enough for a 200 meter sprint) – The only way to get rid of the lactic acid buildup is a chemical pathway that requires extra oxygen. Reason for heavy breathing after a race

Energy and Exercise • For exercise more than 90 seconds, cellular respiration is used for the needed ATPs • Slower than fermentation, so athletes must ‘pace themselves’ • Uses glycogen stores for first 15 to 20 minutes • Then uses other stored energy, like fats • Why aerobic forms of exercise are beneficial for weight control

End of Photosynthesis and Respiration Power Point You will see this again in quizzes and tests! Please Study!